In this work, we studied radio-frequency reactively sputtered molybdenum oxide thin films. Thin films with distinct stoichiometries were obtained by varying the oxygen now and maintaining all other deposition parameters constant. The relationship between optical, electrochemical, and mechanical behavior of the films submitted to lithium intercalation in an aprotic electrolyte is reported. Films deposited at low oxygen flow (B-films) are substoichiometric molybdenum oxide, with composition MoO3-x (0 < x < 1). Films deposited at high oxygen flow (T-films) approach the MoO3 stoichiometry. B-films have a greater concentration of optically active sites and a more open structure when compared to T-films.